The present invention relates to spray drying and similar equipment where means is provided to filter particles from the drying air or other gases at the exit end of the apparatus. A large number of filter devices of this general type are used for drying and other operations where it is necessary to have an almost perfect filtering of the air or other gases exiting from the apparatus and where the filtering materials need to be periodically changed.
A widely used and effective filtering means for this purpose is a bag collector utilizing an array of filter bags mounted at the exhaust end of the apparatus so that the exiting air passes through the filter bags as the dried powder or other particles are removed from the air flow by the filter bags. Even though there are various bag cleaning means including vibrators and pulsing means using air flow reversal, the filter bags periodically become clogged and coated and less efficient. For this reason and because of product changes it is necessary to periodically replace the individual filter bags.
In bag collector systems requiring a highly efficient filtering operation, the individual bag assembly mountings themselves must be absolutely air tight to prevent any air flow other than through the material of the filter bag. This has resulted in relatively complicated attachment means to insure a tight seal and has also resulted in relatively difficult bag change operations.
In a typical spray dryer used in the food processing industry, there may be as many as about 600 filter bag assemblies in a single installation. The periodic change of these bags will require up to 24 man hours for bag removal and an additional 24 hours for bag replacement so that a change-over requires two full days even working around the clock. A further problem in bag changing, in addition to the tight mounting required for a seal, results from the close mounting of the bags for an efficient space saving filter and where access to the individual bag assemblies is therefore restricted and difficult.
The quick change bag assembly of the present invention has a release mechanism whereby it is only necessary to simultaneously lift and twist the bags for their removal and to provide an opposite manipulation in attaching the fresh bag.
Accordingly, an object of the present invention is to provide an improved filter for spray dryers or similar equipment.
Another object of the present invention is to provide a simplified quick change means for replacing filter bags in a relatively large multi-bag filter apparatus.
Another object of the present invention is to provide a simplified and inexpensive quick change filter bag mounting.
Another object of the present invention is to provide a quick change arrangement for filter bags for substantially reducing the changeover time and expense.
Another object of the present invention is to provide a quick change arrangement for filter bags where the changeover time is reduced to less than 1/4 of that previously required.
Other and further objects of the present invention will become apparent upon an understanding of the illustrative embodiments about to be described or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.